Coaxial type of self-mixing interferometer equipped with a wavelength stabilizing system

摘要

Because the wavelength of a laser diode (LD) has the temperature-sensitivity, in conventional LD interferometers, a temperature control is required to stabilize the wavelength in long-term measurements. We propose a self-mixing laser diode interferometer that has two coaxial measurement arms. Two interference signals are used for the measurement of displacement and wavelength stabilization in our system. As the wavelength is not stabilized thermostatically, but by adjusting current feedback, compensation is simple and response-time minimal. The feedback controls for displacement measurement and wavelength stabilization were implemented on a time-sharing basis. The devise we propose enables us to conduct long-term measurements of microscopic levels of displacement.